pudding wrote: ↑Mon May 16, 2022 8:19 am
I can't see or understand why this wouldn't be ok, but the sentence in the DNO's reply above about 'a total of 7.4kW limited down to 3.68kW' seems to imply for some reason that its 3.68kW from the existing solar inverter we already have, and then new 3.68kW from the new batteries inverter, so another inverter for the solar PV, even if limited so as not to exceed a total of 3.68kW export, wont be accepted for some reason? Am I understanding this correctly? Anyone know why if so and whats the point of the 7.4kW value, surely that could be any number as long as the export limit is imposed? And any chance to persuade the DNO to accept any amount of installed generation, as long as the export is limited to 13A overall?
What you are saying is correct up to a point but not necessarily from the DNO's point of view as the max export limit of 3.68 kW needs to be achieved in a 5 second time limit.
The hybrid inverter on its own would do that.
An AC coupled zero export battery storage inverter with an existing standard 3.68kW solar inverter would do that. That's the reason they allow the G99 fast track process.
But fitting a hybrid inverter and setting a 3.68kW limit with an existing standard 3.68kW solar inverter may or may not do that. Therefore it would be a full G99 application and as the total "system" would not be G100 type tested, the DNO may want specific tests to be performed and maybe witnessed. But they seem to have said you cannot even have that option without further network reinforcements.
Last edited by nowty on Mon May 16, 2022 11:17 am, edited 2 times in total.
18.7kW PV > 109MWh generated
Ripple 6.6kW Wind + 4.5kW PV > 26MWh generated
5 Other RE Coop's
105kWh EV storage
60kWh Home battery storage
40kWh Thermal storage
GSHP + A2A HP's
Rain water use > 510 m3
pudding wrote: ↑Mon May 16, 2022 11:01 am
In what way?
From my viewpoint, I can't really see it making a difference connecting new solar PV via a charge controller or inverter in terms of using what it generates.
In the case where the batteries are full and house requires power, over what the existing 4kw array can provide, if the new solar is connected via a charge controller, then it can't provide the extra directly, and the batteries will, with the new PV then charging the batteries as they are used. OR, new solar via an inverter would provide that extra power directly and the batteries stay at 100%. End result should be the same in each case shouldn't it, approximately? Just it's simpler and cheaper with the charge controller.
I had wrongly assumed you were extending a current hybrid system. This would have made the charge controller a more hassle free option.
Do you have a max array size you would like to get to? I ask as there may be wiggle room beyond what the dno allows installed on current regulations for further growth re charge controller. As I said in last post I'd be trying to tie my second pv inverter and hybrid battery side together in one unit. Is that a possibility?
19.7kW PV SE, VI, HM, EN & DW
Ripple 7kW WT & Gen to date 19MWh
42kWh LFPO4 storage
95kWh Heater storage
12kWh 210ltr HWT.
73kWh HI5
Deep insulation, air leak ct'd home
Zoned GCH & Hive 2
WBSx2
Low energy bulbs
Veg patches & fruit trees
pudding wrote: ↑Mon May 16, 2022 11:01 am
In what way?
From my viewpoint, I can't really see it making a difference connecting new solar PV via a charge controller or inverter in terms of using what it generates.
In the case where the batteries are full and house requires power, over what the existing 4kw array can provide, if the new solar is connected via a charge controller, then it can't provide the extra directly, and the batteries will, with the new PV then charging the batteries as they are used. OR, new solar via an inverter would provide that extra power directly and the batteries stay at 100%. End result should be the same in each case shouldn't it, approximately? Just it's simpler and cheaper with the charge controller.
Nothing wrong with that logic but you would require a seperate inverter as well for the batt system so i guess thats how you get back to the hybrid inverter?
Found this one on a quick Google. How does one go about setting the export limit to qualify with dno if need be and then how does dno know that you have left it as is? Always been a grey area in my knowledge. Would be great if you could hook up a unit that could export a low set power to work alongside a primary FIT system yet be able to discharge batteries to home at say 6kW?
19.7kW PV SE, VI, HM, EN & DW
Ripple 7kW WT & Gen to date 19MWh
42kWh LFPO4 storage
95kWh Heater storage
12kWh 210ltr HWT.
73kWh HI5
Deep insulation, air leak ct'd home
Zoned GCH & Hive 2
WBSx2
Low energy bulbs
Veg patches & fruit trees
Keep getting gateway timeout on that link. Same thought here, in that the DNO has to trust that you wont just change the system/setup after installation, but then you'd have no reason/motivation/gain from doing so?
I dont know if my opening post/wall of text was a bit long, but here's a v rough sketch of the 3 options as I see it:-
I'm thinking a hybrid inverter is to be avoided, as we then can't utilise our existing perfect south facing 4kW array to charge the batteries then.
4kW array w/Fronius | 3.51kW & 3.28kW arrays w/Sunsynk 3.6kW hybrid | 6 x Pylon US3000C
8kW GSHP/MVHR/5kW A2A HP/ Ripple- KH & DW & P4 on the way
I have option 1 with an ac coupled hybrid inverter. Works well, beyond this place I'll leave it to others. Just make sure you get the preliminary nod from dno before you spend out.
Last edited by Joeboy on Mon May 16, 2022 12:20 pm, edited 1 time in total.
19.7kW PV SE, VI, HM, EN & DW
Ripple 7kW WT & Gen to date 19MWh
42kWh LFPO4 storage
95kWh Heater storage
12kWh 210ltr HWT.
73kWh HI5
Deep insulation, air leak ct'd home
Zoned GCH & Hive 2
WBSx2
Low energy bulbs
Veg patches & fruit trees
Option 3 requires 3x inverters that take up space and cost more.
I disagree with you about option 2, the hybrid inverter would work to avoid all grid export. It can store electric from your existing array as well as your new panels.
I would go for option 2.
12x 340W JA Solar panels (4.08kWp)
3x 380W JA Solar panels (1.14kWp)
5x 2.4kWh Pylontech batteries (12kWh)
LuxPower inverter/charger
(Artist formally known as ******, well it should be obvious enough to those for whom such things are important.)
Stinsy wrote: ↑Mon May 16, 2022 12:19 pm
Any of those options would work.
Option 3 requires 3x inverters that take up space and cost more.
I disagree with you about option 2, the hybrid inverter would work to avoid all grid export. It can store electric from your existing array as well as your new panels.
I would go for option 2.
P.s.option 2 was my original system at 5.12kw but without the exra panels. I then added the charge controller and further panels. I mention this as you would have a further expansion option beyond your planned expansion if you feel you could use even more PV later and go for option 2 now.
Last edited by Joeboy on Mon May 16, 2022 12:26 pm, edited 2 times in total.
19.7kW PV SE, VI, HM, EN & DW
Ripple 7kW WT & Gen to date 19MWh
42kWh LFPO4 storage
95kWh Heater storage
12kWh 210ltr HWT.
73kWh HI5
Deep insulation, air leak ct'd home
Zoned GCH & Hive 2
WBSx2
Low energy bulbs
Veg patches & fruit trees
Really, a hybrid inverter would be able to charge from the existing 4kW array? I didn't think they could, maybe I've misunderstood and that then would be the best way forward after all. I always thought it had to be an AC coupled inverter to be able to benefit from an already existing solar PV array? That changes things.....
4kW array w/Fronius | 3.51kW & 3.28kW arrays w/Sunsynk 3.6kW hybrid | 6 x Pylon US3000C
8kW GSHP/MVHR/5kW A2A HP/ Ripple- KH & DW & P4 on the way
In case of a mains power cut, if the hybrid inverter can still charge the batteries and supply limited mains type power (with restrictions) that might also be beneficial.
I believe some hybrid inverters can also take 2 mppt inputs, so it would be easy to add another pv array later even if pointed in a different direction.
